Tuesday, 16 January 2007: 11:30 AM
Tropical Cyclone Wind Probablities: Better Defining Uncertainty at the National Hurricane Center
214C (Henry B. Gonzalez Convention Center)
Tropical cyclone surface wind speed probabilities text and graphical products issued by the Tropical Prediction Center/National Hurricane Center (TPC/NHC) became operational at the start of the 2006 hurricane seasons in the Atlantic and eastern North Pacific basins. The underlying techniques were developed by researchers at NOAA and Colorado State University, while the products themselves were developed by the Technical Support Branch (TSB) at TPC/NHC. The tropical cyclone surface wind speed probabilities products provide probabilities of sustained (1-minute average) surface (10-meter altitude) wind speeds of at least 34 kt (39 mph, tropical storm force), 50 kt (58 mph), and 64 kt (74 mph, hurricane force) at individual locations in the Atlantic and eastern North Pacific basins. The probabilities are based on errors during recent years in the official track and intensity forecasts issued by the TPC/NHC. Variability in tropical cyclone size (wind radii) is also incorporated. A previous product - the discontinued strike probabilities - was a statement about the "close" approach of the center of a tropical cyclone. However, the wind speed probabilities products are about the weather. That is, the wind speed probabilities provide the chances of wind speeds equal to or exceeding familiar thresholds (for example, tropical storm force and hurricane force) at individual locations. Therefore, these probabilities likely have more direct meaning and impact to users.